Web tension control for printing presses



May 5, 1953 K. G. LAYcocK 2,637,506 WEB TENSION CONTROL FOR PRINTINGPRESSES Filed Nov. 4, 1950 2 SHEETS-SHEET l L ao du r 1 /l T TORNE Y.

May 5, 1953 K. cs. LAYcocK WEB TENSION CONTROL FOR PRINTING PRESSESFiled Nov. 4, 1950 2 SHEETS-SHEET 2 NNN IL ww w K s L gf fm u Il maw Wwwwwza m W Y NN A... m .www M /V/ NWA QN [mi QN m v.. C nvI I B yPatented May 5, 1953 UNITED STATES PATENT OFFICE WEB TENSION CONTROL FORPRINTING PRESSES 12 Claims.

The present invention has for its object the provision of a novel andimproved tension mechanism for controlling the tension of web fed from aweb roll to a printing press.

Objects and advantages of the invention will be set forth in parthereinafter and in part Will be obvious herefrom, or may be learned bypractice with the invention, the same beingl realized and attained bymeans of the instrumentalities and combinations pointed out in theappended claims.

The invention consists in the novel parts, constructions, arrangements,combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a parthereof, illustrate one embodiment of the invention, and together withthe description, serve to explain. the principles of the invention.

Or the drawings:

Figure l is a schematic side elevation, partly in section of a typicaland preferred, illustrative embodiment of the vpresent invention; and

Figures 2, 3, fi and are detailed vertical sections taken on the lines 22, 3--3, 4-4 and 5-5, 'l

respectively, of Figure 1.

The present invention has for its object the provision of a novel andimproved web tension mechanism for printingl presses which produces amore uniform control of the web tension than has heretofore beenattained by the mechanisms generally used for this purpose. A furtherobject is the provision of an improved mechanism for controlling thetension of a web by means of moving belts or other driven frictionmembers in fric- 'tional contact with the web supply roll, so as tomaintain a constant tension on the running web and at the same time toslow or stop the web roll as the press slows down or as a break occursin the web. rihe invention further provides a simplified form of webtension mechanism which requires no complex or separate source oi powerfor its actuation and which is completely reliable in its operation. Ypresent invention provides an improved web tension mechanism which is ofthe general type disclosed in the patent to Stone, 1,722,508 of i929,but which provided no variable control for Ythe friction exerted on theweb supply roll.

According to the present invention, one or more web supply rolls aresupported for rotation so that successive web rolls may be brought intoweb feeding position and the active web roll,

is engaged by a set of slowly moving belts, spaced across the width ofthe roll and pressed into and maintained in firm frictional Contact withthe surface of the active web roll so that the difference in speedbetween the belts and the surface of the web roll exerts a regulabledrag' on the roll to create the desired tension in the web fed to theprinting press. The friction belts are preferably driven from andproportionally to the speed of the press and are also subject to theaction of brake mechanism which serves to regulate the pressure betweenthe belts and the web roll. The belts each pass over two pulieys, one ofwhich is a driving pulley and the other of which is a brake pulley sothat the constant driving of each belt maintains contact with the webroll while the pressure of this contact is regulated by the effortexerted on the belt by the brake mechanism.

For maintaining the web tension constant by variation of thebelt-braking effort, the web passes over a pilot roller on its way tothe press, the pilot roller being substantially counterbal anced so thatit may be readily moved by changes in the web tension. Included in thecounterbalaneing means, and for opposing the action of the web tensionon the pilot roller is a resiliently supported large mass which exerts asteady force on the pilot roller and is .so resiliently suspended thatminor and sudden movements of the pilot roller cause substantially nomovement of the mass, Thus, the mass is moved only by continued or slowmovements of the pilot roller, and the pilot roller may move much morerapidly than if a corresponding movement of the mass were necessary.

Means are also provided for allowing the mass to move more freely in onedirection than the other so as to eliminate the possibility of continuedoscillation of the pivotally and resiliently mounted pilot roller.

The brake means acting on the web roll engag-ing belts areinterconnected so that the belts exert a substantially equal pressure onthe web roll, and these brake means are preferably of theself-energizing or servo type so that a slight increase in the pressureapplied to the brake causes a greater increase in the braking effortexerted by the brake.

The brake means are preferably interconnected with and controlled by thepilot roller so that the apparatus as a whole is controlled by theactual web tension and any increase or decrease in the web tension fromthe normal value causes a compensatory change in the braking force eX-erted on the belts and likewise a change in the f drag exerted by therunning belts on the web roll, so as to maintain a constant web tensionat the desired value.

It will be understood that the foregoing general description and thefollowing detailed description as well are exemplary and explanatory ofthe invention but are not restrictive thereof.

Referring now in detail to the present preferred and illustrativeembodiment of the invention, the tension mechanism is shown as appliedto a conventional magazine reel I9 adapted to rotatably support anactive web roll I2 from which a web of paper i4 is fed to the printingpress (not shown), reserve web rolls I6 of paper being supported by thereel II) so they may be brought successively into web feeding positionby rotation of the web reel I about its shaft I8 fixed in the pressframe 2U.

In being fed to the press, the web I4 passes over` guide rollers 22 andis looped around a pivotally mounted pilot roller 24, 'the position ofthe pilot roller being determined by the tension of the web drawn fromthe web roll I2.

Rotation of the active web roll I2 is opposed and tension on the runningweb I4 is created by means of a plurality of similar endless belts 26formed of friction material, such as fabric, the several belts beingspaced apart longitudinally of the web roll, and being supported so thateach normally makes arcuate Contact with the web roll, and travelrelatively slower than the surface of the web roll I2, thereby creatingfriction or drag, the amount of which depends on the pressure betweenthe belts 26 and the web roll I2, the angular extent of the Contactbetween them, and to a slight extent on the difference in speed betweenthe belts and the surface of the active web roll.

As embodied, each of the belts 26 is supported by means of a pair ofpulleys 28, 29 one above and one below the web roll I2 and so positionedthat the reach of the belt 26 towards the web roll I2 will wrap the webroll I2 for a substantial arc whether the web roll is large or almostexhausted.

Cooperating with each of the pulleys 28, 29 are means for preventingslippage of the belt on the surface of the pulley and for this purpose asupplemental belt 36 is provided for firmly holding the friction belt 26on the pulley, the supplemental belt 30 running freely over two idlerpulleys 32 and a resiliently mounted slack take-up pulley 34, thepulleys 32 and 34 being positioned to provide a large Wrapping Contactbetween the belts 26 and 30.

The speed of running of the belts 26 is controlled by driving the beltsfrom the printing press and for this purpose the pulleys 28 are allkeyed to a shaft 49 which is journalled in the press frame 20 and isdriven from the press through chain 4I and sprocket 42, the speed ofdriving being a small fraction of the press speed so that the belts 26preferably have a surface speed of about of the web speed.

The pressure of the belts 26 against the surface of the web roll ispreferably controlled by means of a brake actuated by movement of thepilot roller in response to changes in web tension, the brake serving toexert a drag on the belts 26 as they are driven from the press. Asembodied, eachof the belts is provided with its individual brake meansin the form of a brake drum 44 keyed to the corresponding belt pulley29, so that, with the cooperation of the corresponding supplemental belt36, the belt 26 is retarded to exert a variable pressure and drag on theweb roll I2.

A deflector plate 2I is provided for the return reach of each belt 26 toguide the belts 26 and prevent the slack from fouling the belts, each ofthe deflector plates being mounted on a cross frame member 21.

Each of the brake drums 44 and belt pulleys 29 is mounted for rotationon a shaft 46 which is supported in pairs of upright frame members 48,one such pair being provided for each belt 26 and in the frame 26 at theends of the shaft 46.

Cooperating with each brake drum 44 is a pair of arcuate brake shoes 56,5I mounted for movement toward and from the brake drum 44. Shoe 56 iscarried by a plate 52 above the drum 44 while shoe 5I is mounted on thelower plate 53, the two plates being connected together by means of thepivotal link 55 so that the shoes 50, 5I may press against the drum 44.The other end of plate 52 has a normal position and braking pressure onthe shoes is normally provided and maintained by means of resilientpressure on the other end of the lower plate 53, through spring 51 whichis compressed between the end of the plate 53 and an end of the weightedbell crank 58 which is pivotally mounted for oscillation on shaft 46,and is limited in oscillation by stops 66 on an adjacent frame member 26or 48. The weighted bell crank is normally held by the upper stop 60 andthe brake is normally energized by the pressure exerted by spring 51 onthe lower plate 53 of the brake, but the braking force can be greatlyincreased by rotation of the brake as a whole so that bell crank 58engages the lower stop 66 and spring 5l is compressed more than normal.The normal braking force on each of the belts 26, and on the web rollmay be varied by movement or replacement of the weight 62 on bell crank58.

For controlling and varying the braking force and thereby regulating thetension of the web fed to the printing press, the pilot roller isconnected to the brake mechanism by means of a flexible cable 66 whichis preferably interconnected to the several brake mechanisms so as toequalize their action. As embodied, the cable 66 is xed to a drum 61 onthe shaft 68 by which the pilot roller 24 is pivotally mounted and isconnected to one end of the brake shoe supporting plates 52 so thatpivotal movement of the pilot roller 24 on decreasing tension of the webI4 causes the upper plate 52 to be pressed more powerfully against thebrake drum 44.

Cable 66 passes over guide pulleys I2 and runs over pulley blocks 'I0which are connected by cables 'I3 to the free end of each upper plate52, while the end of cable 66 is anchored by means of a relatively heavyweight 'I4 which normally rests on the floor. The force thus appliedthrough the pulley blocks I0 and cables 66 to the several braking meansis equalized. The maximum braking force which can be applied is thuslimited by the mass 0I" weight 'I4 which is lifted from the floor on anextreme movement of the pilot'l roller 24.

Means are provided for substantially counterbalancing the pilot roller24 on its pivotal mounting 68, and also for moving the pilot roller asthe web tension slackens and for opposing movement of the pilot rolleras the web tension ncreases. As embodied, pilot roller 24 is rotatablymounted at its ends in arms which are keyed to the rotatable shaft 68,at least one of these arms extending to the other side of the shaft 68so that it provides a mounting for counterweight 82 which may be held invarious radial positions by means of its set screw 84, thereby providinga means for accurately counterbalancing the pilot roller 24 when theother forces acting on the roller are disregarded. For urging the pilotroller against the tension of the web at the pilot roller loop, a cable86 .extends downwardly and is fixed at its upper end to the pulley 61',fast on shaft 62. Cable 86 supports the relatively heavy masses A88 and89 `which correspond to the tension desired to be established on the webby the action of the friction belts 26 bearing against the running webroll |2. The masses 89 are preferably in the form of removable weightswhich can be removed or replaced to adjust the tension of the web to thedesired value.

The tension creating masses 8.8 and 89 are resiliently supported fromthe cable vllt, and such resilient support is preferably provided bymeans of a spring 90 interposed in the suspension systems between thecable 86 .and the masses 88, 89. As shown, cable 86 is connected to avertically extending guide rod 02 by means of yoke `94, guide rod 92 isguided in guide brackets 95 mounted on the side frame 20, and at itslower end, is pivotally connected to a lever arm 98 which is alsopivotally connected to link 09 extending upwardly from the lever arm |90which is pivotally connectedto a guide rod |01 forming the mountingmember for the masses 88 and `89. The link 90 is preferably adjustabletolever |00 While the upper end of link 99 is variably pivoted by meansof `a pivot pin which may be inserted in any one of the holes |03.Positioned between the link 99 and the vertically aligned guide rods 92and 10| is a link |04 pivoted at its lower end to the lever |00, andslidable in a bushing |05 which is pivoted to the upper lever 90. Theupper end of the link |04 carries compression spring 90 which isvariably compressed between the bushing |05 and nut |06, therebyproviding a variably resilient suspension system for the masses 88, 89so that minor and sudden movements in the position of the pilot roller24 caused by quick changes in the web tension are absorbed withoutcausing substantial movement of the masses 80 and 89..

Spring means are provided for limiting upward motion of the cable 8e andfor this purpose a coil spring |08 is wound around the guide rod 92 andis supported on collar |09 serving as a resilient stop to engage thelower. portion of guide bracket 96.

`A similar resilient connection is provided in the flexible cable 66 sothat movements of the pilot roller 24 are resiliently transmitted to thebrake systems for the running belts '25. While this resilient connectionmay be a duplicate of that just described, it is preferably additionallyprovided with means for minutely adjusting the position of the link S9with respect to the vertically extending rod IIB and cable end l whichcorresponds to the rods 92 and lill, respectively. The minute.adjustment of link Sil is effected by means of a threaded member H2provided with a hand wheel H4 rotatably mounted and held against axialmovement by bracket HE, r

end of link .99 is provided with a pin .l I8 which `is slidablysupported in slot |20. The upper end of rod ||0 is preferably .connectedto the upper portion of .cable 06 by means of a turnbuckle so that theeffective length of the cable 66 may be adjusted to provide the desiredposition of the pilot roller 24 for a normal setting of the brake.

Additional snubbing means are provided for allowing the pilot roller 24to move downwardly on decreasing tension more easily than it is al`lowed to move upwardly on increasing tension. For this purpose rod |0|is provided with a wedge shaped member |22 tapering upwardly, the sidesof the wedge engaging with friction pads |24 mounted on the inner endsof slide blocks |26 which are slidably mounted in guides |28 fixed tothe side frame 2t, the friction faces |24 being pressed inwardly intoresilient engagement with the wedge faces |22 by means of levers |30pivotally vmounted above the guides |28. The upper ends of levers |3|lare provided with threaded members |32, the inner ends of which compresssprings |34 against the bracket |36 mounted on the side frame 29,thereby providing variable resilient pressure on the friction members|24 so that the degree of snubbing of the movement of the masses 88 and39 may be controlled as desired.

In operation, the web is threaded from the web roll to the press to forma loop around the pilot roller 24. The pilot roller counterweight 82 isadjusted so that the pilot roller supporting arms 0i! assume asubstantially horizontal position. Sufficient weights 8.8 and 89 areused to provide a downward pull on the pilot roller 24 which willnormally equal the desired tension on the full web I4 as it is fed tothe press. The rollers 34 are adjusted so that the belts 30 firmly holdthe running belts 26 against the pulleys on which they are mounted, andthe springs 00 and |34 are adjusted to give the desired degree ofresiliency, while weights 52 are positioned so as to create the desiredbraking force on the several running belts 26..

The printing press is now placed in operation and the web is drawn fromthe active web roll l2 at the same time that the belts 26 are `slowlydriven from the press, the feeding of the belts being opposed by theseveral brake shoes 5|] and 5l so that the belts 2t are more or less`freely engaged with the surface of the web roll I2 to oppose rotationof the Web roll,

A gradual increase in the tension of the web causes pilot roller 24 toraise, thereby slackening the cable 66 and diminishing the pressure withwhich the bra-ke shoes 50 and 5| are pressed toward each other andallowing the belts 26 to be fed more readily so that the pressurebetween them and the web roll |2 is diminished to allow the web roll torotate more freely thereby reestablishing the original desired tension.At all times braking pressure between the brake shoes 53 and 5| iscontrolled by the force exerted by the weight S2 as transmitted throughthe spring 5l which controls the feed of the belts 25 and thereby thepressure of the belts on the web roll.

Irregularities in the running of the web rolls l2 are compensated for bythe interconnection of the several brake mechanisms tothe pulleys l0 andcable 56 so that a deformed or irregular roll can operate smoothlyWithout creating sudden ined'alities in the web tension.

Sudden minor variations in the Web tension cause corresponding movementsof the pilot roller tions so that no substantial movement of the masses88, 89 or of the brake cables 'I3 occurs.

-However, gradual changes in web tension are transmitted to the sever-albrakes and the force usually applied to the cables I3 and thecorresponding brakes is the force exerted from the masses 88 and 89. Thewedge member |22 allows the brakes to be applied rapidly in case of anemergency shutdown of the press and also allows the masses 88 and 85 tomove downwardly more easily than upwardly so that a gradual increase inthe braking force exerted between the brake shoes 5U and 5I occurs,compensating for the reduced angle of the arcuate contact between thebelts and the web roll I2 which occurs as the web roll is used up. Anygradual increase in the web tension causes the pilot roller 24 to moveupwardly thereby allowing the brake shoe 50 to move very slightly awayfrom the brake shoe 5I so that the upper stop 80 prevents fullapplication of the pressure created by weight 62 to force the brakeshoes together and resulting in a reduction in the pressure between thebelts 28 and the web roll I2 so that the web I4 is more easily fed fromthe web roll I2 thereby restoring the web tension to the desired normalvalue.

In the case of a web break or a sudden slowing or stoppage of theprinting press, pilot roller 24 moves rapidly downwardly under theinfiuence of weights 88, 89 tending to lift or actually lifting theweight 'I4 and causing each of the brakes to be rotated counterclockwise(Figure 1). -As

vthe brake shoes 50, 5I and their supporting memvbe further compressedand providing additional pressure on the brake shoes 50, 5I so as tocause a tightening of the belts 26 against the web roll I2 and anincreased dra-g on the web roll which produces an increased web tensionto slow or stop the running web roll.

The invention in its broader aspects is not limited to the specificmechanisms shown .and

described but departures may be made therefrom within the scope of theaccompanying claims without departing from the principles of theinvention ,and without sacrificing its chief advantages.

What I claim is: y

1. In a tension device for tensioning the web as it is fed from a webroll to a printing press, the combination of means for rotatablysupporting a web roll, a running belt driven from the press at a smallfraction of the speed of the running web to be pressed against thesurface of the web roll to exert a drag thereon, a counterbalanced pilotroller over which the web is fed normally urged by means of aresiliently suspended mass against the tension of the web looped aroundit, a brake restraining feeding movement of the running belt to vary thepressure of the belt against the web roll, and means `for controllingthe action of the brake on the running belt by the tension of the web asmeasured by the pilot roller.

2. A tension device as claimed in claim 1 in which snubbing means areprovided acting on ltheV mass to damp its motion.

3. A tension device as claimed inclaim 1 in Which there are provided aplurality of running belts each provided with a pilot-roller actuatedbrake and the brakes are interconnected for equalized actuation by thepilot roller. J

4. In a web tension device to cooperate with a rotatably supported webroll feeding web to a printing press, the combination of a press-drivenrunning belt to be pressed against the surface of the web roll, a brakerestraining the free running of the belt, a pilot roller moved bychanges in lthe tension of the web drawn from the web roll,

a resiliently suspended mass tending to move the pilot roller as the webtension decreases and means controlling the action of the brake on thebelt by movement of the pilot roller.

5. In a web tension device to cooperate with a rotatably supported webroll feeding web to a printing press, the combination of a plurality ofpress-driven running belts to be pressed into engagement with thesurface of the web roll, individual brake means controlling the freerunning of the belts to control their pressure on the web roll and theweb tension created thereby, flexible cable means interconnecting theseveral brake means for pressing the belts into contact with the webroll and for equalizing the action of the several belts on the web rolland for controlling the action of the several brakes.

6. A web tension device as claimed in claim 5 in which the cable isanchored at one of its ends by means of a weight having a normalposition from which it may be freely lifted.

'7. In a web tension device, the combination of means for rotatablysupporting a web roll, a pilot roller moved by changes in the tension ofa web fed to a printing press, brake means act- 'ing on the web roll fortensioning the web, said brake means comprising a rotatable brake drum,a pair of relatively movable brake shoes engageable with the brake drum,a weighted bell crank, a spring connecting the weighted bell crank withone of the brake shoes and forcing the shoe against the brake drum andmeans interconnecting the other brake shoe for movement by the pilotroller.

8. A tension device as claimed in claim '7 in Vwhich a pair of stopslimit movement of the bell crank in either direction as it is moved bythe pilotlroller acting on the brake shoes.

9. In a web tension device for tensioning web as it is fed from a webroll to a printing press, the combination of means for rotatablysupporting a web roll, a plurality of running belts to be pressedagainst the surface of the web roll to exert a drag thereon, the runningbelts being driven from the press at a fraction of the speed of therunning web, a brake acting on each runningbelt to restrain its freerunning and to press the belt against the web roll surface, a weightnormally actuating the brake, a pivotally mounted pilot roller moved bychanges in web tension and about which the web is looped as it is fed tothe press, a counterweight for balancing the pilot roller in its pivotalmounting, a resiliently suspended mass urging the pilot roller againstthe tension of the web, and means interconnecting the running belts witheach other and with the pilot roller with the brake whereby the actionof the weight on the brake may be varied by movement of the pilot rollerin response to changes in the tension of the web.

10. A web tension device as claimed in claim 9 in which several brakesand running belts are provided, and a flexible cable forms the connec- 9tion between the pilot roller and the several brakes, the cable islooped between guide pulleys over pulleys individually connected to theseveral brakes and the end of the cable away from the pilot roller isanchored to a Weight which may be freely lifted.

11. In a tension device for tensioning the web as it is fed from a webroll to a printing press, the combination of means for rotatablysupporting a Web roll, a pair of spaced apart belt pulleys over which abelt runs in position to press against the surface of the web roll, oneof said pulleys being driven at a small fraction of the surface speed ofthe web roll and in the same direction While web is fed to the press andthe other being braked, means cooperating with the belt pulleyspreventing slippage of the belt on the pulleys, and means for varyingthe braking force applied to the braked pulley whereby the pressureexerted by the belt against the web roll 20 10 is changed to vary thetension of the web fed from the web roll to the press.

12. A tension device as claimed in claim 11 in which the braked pulleycooperates with a pilot roller moved by changes in the tension of theweb feed and the braking force on the pulley is varied by movement ofthe pilot roller.

KENNETH G. LAYCOCK.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,868,310 Cline July 19, 1932 1,904,870 Laycock Apr. 18, 19331,937,412 Roesen Nov. 28, 1933 1,972,916 Broms Sept. 11, 1934 2,000,918Broms May 14, 1935 2,002,011 Horton May 21, 1935 2,005,738 Foster et al.June 25, 1935 2,085,889 Ball July 6, 1937

